Solar System

5. Any interaction with an object that, if unopposed, will change the motion of the object.
6. A cloud of gas and dust in outer space.
8. Cosmic snowballs of frozen gasses, rock, and dust that have an elongated orbit around the Sun.
10. A system of millions or billions of stars held together by gravitational attraction.
12. The amount of matter which an object contains, the measure of inertia that an object has.
13. A meteor that has impacted the surface of Earth.
14. A planet that is composed primarily of silicate rock and/or metals.
16. A meteoroid that has entered Earth's atmosphere.
17. Along with mass, this is a factor that determines gravitational force between two objects.
18. Force in opposition to the motion of an object as it passes through the air.
19. The tendency to do nothing or remain unchanged.

1. A natural satellite of any planet.
2. The most widely accepted theory of solar system formation.
3. The collection of eight planets and their moons in orbit around the Sun, together with smaller bodies in the form of asteroids, meteoroids, and comets.
4. The force that attracts an object having mass towards another object having mass.
7. Force that resists the sliding or rolling of one object over another.
9. The curved path of a celestial object around another object with more mass.
10. Large planet consisting of low density gasses and ice. Examples include Jupiter and Saturn.
11. A small body in space, often a chunk of an asteroid. Could become a meteor if it enters the Earth's atmosphere.
12. The galaxy in which our solar system resides.
15. Small rocky body that orbits the Sun.